12_InstSolManual_PDF_Part11

12_InstSolManual_PDF_Part11 - 3.16 3 10 5 21 1 3 10 2 12 W...

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12.38. Set Up: The sound waves it produces have the same frequency as the standing waves on the wire. The second overtone is the third harmonic, with Solve: (a) and (b) the same as for the wire. is larger in air because is larger there. 12.39. Set Up: Solve: (a) The boundary surface between the two materials cannot create or destroy waves; the number entering one material per unit time must equal the number leaving the other material in the same time. Since and doesn’t change, if changes then the wavelength must change. (b) is the same, so Reflect: The wavelength is larger in the material where the wave speed is larger. 12.40. Set Up: and Solve: (a) (b) (c) All the power radiated in one second is received by the walls of the room in one second. Each second the walls receive 511 J. 12.41. Set Up: with If then Solve: (a) gives and (b) gives and I 5 1 10 9.2 21 1 3 10 2 12 W / m 2 2 5 1.58 3 10 2 3 W / m 2 9.20 5 log 1 I I 0 2 b5 92.0 dB I 5 1
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Unformatted text preview: 3.16 3 10 5 21 1 3 10 2 12 W / m 2 2 5 3.16 3 10 2 7 W / m 2 I I 5 10 5.5 5 3.16 3 10 5 . 5.50 5 log 1 I I 2 b 5 55.0 dB y 5 10 x . x 5 log y I 5 10 2 12 W / m 2 . b 5 10 log 1 I I 2 , I 2 5 I 1 1 r 1 r 2 2 2 5 1 6.50 W / m 2 2 1 2.50 m 7.00 m 2 2 5 0.829 W / m 2 P 5 I 1 4 p r 2 2 5 1 6.50 W / m 2 21 4 p 21 2.50 m 2 2 5 511 W I 1 I 2 5 r 2 2 r 1 2 P 5 I 1 4 p r 2 2 l water 5 l air 1 v water v air 2 5 1 2.50 m 2 1 1498 m / s 344 m / s 2 5 10.9 m v air l air 5 v water l water . f 5 v l l v f v 5 f l v 5 f l v l l 5 v f 5 344 m / s 137 Hz 5 2.51 m f 5 137 Hz, 1 Note: 3 l 2 5 L 2 l 5 v f 5 68.3 m / s 137 Hz 5 0.50 m f 5 3 v 2 L 5 3 1 68.3 m / s 2 2 1 0.750 m 2 5 137 Hz v 5 35.0 N 1 5.625 3 10 2 3 kg 2 / 1 0.750 m 2 5 68.3 m / s. f 5 3 f 1 . l 5 v f . f 1 5 v 2 L . v 5 F T m . Mechanical Waves and Sound 12-11...
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This note was uploaded on 03/06/2009 for the course PHYS 114 taught by Professor Shoberg during the Spring '07 term at Pittsburg State Uiversity.

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